Process of galvanizing metals



H. C. STEFFEN.

,PROCESS OF'GALVANIZING METALS. APPLICATION FILED IAN. 2. 1919.

1,334, 183. PIenIed Mar. 16, 1920.

. 2 SHEETS-SHEET I.

l la

44,- ATTORNEY.r

H. C. STIEIIFINI PROCISS 0F GALVANIZING METALS.

.APPLICATION i FILED JAN. 2,1919.

Patentefi MM.; 16, 1920.

2 5HEET3-SHEET 2.

' ROBERT STEFFEN, OF MIDDLETOWN, OHIO.

PROCESS OF GALVANIZING METALS.

To all whom it may concern:

Be it knovvn that l, ROBERT C. Swinnen', a citizen of the United States, residing at Middletown, in the county of Butler and State of hio, have invented certain new and'useful improvements in the Processes of Galvanizing Metals, of which the following is a specification.

This invention relates to a process of galvanizing metal which is more expeditious and efficient, and considerably cheaper, than any knovvn processes employed for that puratthe intake end for the metal sheets and above which it will bubble. More or less spelter will therefore come in Contact With the metal sheets during their entire course through the lead agent, and impart to said sheets a thicker coating than lthey should rev ceive to avoid the following objections. A.

thick coating of spelter on the sheets, breaks, peels or scales when those sheets are stamped, formed or severely bent, exposing the scaled surface to the corrosive action of the elements. lt is, therefore, one object of my invention to form a much lighter coating on f the metal sheets than can be produced by any lniown processes of galvanization, by first passing those sheets through the preheating agent, and thereafter through an amalgainating agent in contact with only a part of the surface of the `latter and heated by an independent unit.

llt isa further object of my invention to provide a more economical and efficient process for applying a regular or heavy coating to sheet metal with spelter, by first passing the sheet through spelter, then through lead and thereafter through spelter, keeping the two metals at different operating tempera-l tures by independent heating units, and being-able, by varying the depth `of the spelter Specication of Letters Patent.

Patented Mar. 16, 1920.

Application filed January 2, 1919.' Serial No. 269,237.v

iniits independently heated boxes, to deli-4 nitely control the Weight or thickness of the spelter coating formed on the inetal sheets.

When. lead is heated beyond its melting point-Which must be done under the present method ofgalvanization in order to melt the spelter---ijJ rapidly oxidizes, forming lead oXid Which clings to the metal sheet in the form of oXid spots, thereby preventing a uniform coating of spelter upon the sheet. @ne of these oXid spots, when exposed to the corrosive action of the elements, might be sufficient to ruin a Whole sheet of metal. lt is, therefore, a further object of my invention to eliminate these oXid spots, by providing a process of galvanization in` which the lead is not called upon to heat the spelteiI whereby it need not be heated beyond its -melting point to a degree where lead oxid is formed. Accordingly, the sheets in passing through the lead agent will have no lead oxid spots formed on them.

Another object of lny improved process is to reduce the amount of dross formed when the zinc of the spelter comes in cont-act with iron from the sides of the pot and the metal sheets passing through the latter. lBy-rediicing the area of contact of the spelter with the lead, my invention eliminates approximately 75% of dross formation in 'the operation of galvanizin'g. Dress cent. of it will not only lower the efficiency of the spelter by converting it into a nonusable or injurious composition, but will reduce the life of the iron pot, costing from $500 to $600, to about sin or seven months.

A further object of my invention is to effecta saving in the loss of spelter due to onidation. Under [my process, instead of having a large surface of spelter exposed to the air, only a small area is thus exposed, whereupon less zinc is permitted to combine with the oxygenof the air to form zinc oxid. Another object of my improved process is to expeditiously and economically remove the scale formed by the amalgamated spelter on thel exit rolls. Under the present method of changing the rolls, which takes place about once or twice a Week, they will frequently buckle, due to the upper half of the roll being exposed to a higher temperature than thelower half during their reinsertion. In other Words, they are only half is ex- Itremely objectionable, because a small per f them, but the rolls themselves will be presubmerged, exposing them to uneven temperatures which result in buckling. Buckled v rolls, because of their uneven contact with l` lowing reasons. Y

Lead, as 1s well known in the art, prepares 160 the flat sheets, distribute an uneven coating of spelter upon them, forming a thin coating in one place and a thick coating in another. By completely submerging the exit -rolls in the lead agent, heated at a higher temperature than the melting point, the scale will not only be readily removed from vented from-buckling due to their uneven temperature when only half submerged in the spelter after reinsertion under the old method.' While the rolls are thus being cleaned, the dross in the small quantity of spelter above, may be spooned or dipped out Without thepnecessit of removing the entire guides as is done under the present method. Time' and labor are thereby materially saved, and the quantity of spelter required for galvanizing is greatly reduced by reason of the small area it occupies above the lead as compared with the large area it must have under v1ew thereof, partly in section.

Throughout the specification and drawings, similar reference characters denote corresponding parts.

My improved process consists first in filling 'a regular iron pot 1 with lead, said pot being set in a brick heating unit 2 provided 4with a heating chamber 3 andgas intakes 4 as shown. The lead, which will be desig- 11 ated by the numeral 5, supported at one end,

instead of over itsY 'entire surface, a small quantit of spelter 6 bottom ess box 7 whose sides extend into the lead 5 as shown in 1 and 2. Gas

torches8, which project their fiame into conj tact with the sidesof the box 7 above the, Vlevel of the lead 5, su

ply independent heat to the spelter 6 whic vunder my improved process 1s not melted by the lead for the folthe metal sheets to receive the spelter, by preheating them. The approximate melt-A mg point of lead is 600 F.; that of 800. Spelter, being of less specific than the lead, rests u n it; and if, in addition, it derived suiclent heat from the lead that is contained in a v spelter,

to melt it, it would be necessary to heat the latter 200 above itsmeltin point. At that temperature, the lead wou d have such an affinity for absorbing spelter, that the latter would mingle through it. The metal sheets which enter the lead between semicircular guides 9 9 that extend from one upper end of the pot 1 into the spelter 6 at the other end,

of the metal at that point to the corrosive action of the elements. To overcome this objection, my process provides for melting the spelter by the independent torches 8, and not by the lead upon only a small portion of Whose surface the spelter rests as compared with the entire u'pper area thereof which it occupies under the known method. Therefore, the lead need not be heated 200o above its melting point to melt the spelter, for this is taken care of by the independent heating unit, and for this reason it follows that no spelter Willbe absorbed by the lead to make the spelter coating on the metal sheets unduly thick. The metal sheets will be coated with spelter only as they travel through the small portion thereof confined within the bottomless box 7, and this coating there received Will be thin enough to meet the objections heretofore brou ht out.

However, if a thicker coating o spelter is desired, or it is desired to control the weight of spelter put upon the sheet metal in t. e operation of galvanizing, my process contemplates the provisionat the other end of the iron pot 1, of a second auxiliary bottomless box l0 whose sides extend into the lead 5 on each side of the intake ends of the guides 9 9. This box is independently heated by a gas torch 11, and is adapted to receive spelter in the same manner as the box 7. Accordingly, the metal sheets may thus be made to pass throughspelter at the intake and exit ends of the machine, and by regulating the depth of the spelter in both auxiliary boxes 7 and 10, the weight .of spelter or coating thereof on the metal sheets can be definitely controlled. The necessity for tWo separate galvanizing units is thereby obviated by simply introducing spelter into the second auxiliary box 10 above described. A considerable saving in thel amount of spelter required under my p rocess of galvanizing is effected, for in elther instance the spelter does not cover titl till

the entire area of the upper surface of the lead, but only a relatively small portion thereof..

My improved process not only produces a uniformly distributed and permanently adherent coating Vof spelter whose Weight may be regulated, -to a point, if desired, 7vhere it is lighter than that formed on metal by any known method, but it effects a vast saving in the time, labor and equipment required for galvanization. 1n the first place, since the spelter covers such a small surface of the lead, much less spelter is required. 1n the second place, hot spelter when absorbed by the lead, eats through the iron pot into the heating chamber, with the result that the usefulness of the entire galvanizing unit will be destroyed, requiring quite an outlay -for the time, labor and material necessary for its. replacement. Under my process the spelter can only eat through the auxiliary boxes 7 and 10, and these may be replacedat small cost.

Furthermore, less. spelter will be lost through oxidation under my process of galvanizing, since only a small amount of it is exposed to the air as compared with the large area' exposed thereto under the known methods of galv'anization.

By reducing the area of contact of the spelter with the lead, my improved process eliminates approximately 75% of the dross formed under the known methods of galvanizing. The zine of the spelter when it comes in contact with the iron of the metal sheets and that of the' sides of the pot l, forms dross. rlhe latter lowers the etliciency of the spelter, because even a small per cent. of iron is sufficient to convert the amc of the spelter into a non-usable, injurious composition. Dress, of course, will be formed in the auxiliary spelter boxes, but in a quantity which is small in comparison with that formed where the spelter covers the entire upper surface of the lead; and furthermore, that which does form may readily be removed as will hereinafter be described.

Another objection which my proces of galvanizing eliminates, is-the formation of lead oxid spots on the metal sheets as they travel through the lead solution. Under known processes, where the lead is heated beyond its melting point in order to melt the spelter that rests upon it, it rapidly oxidizes, forming lead oxid which produces oxid spots on the metal sheets, thereby preventing a' uniform coating of spelter upon them. 'llhese oxid spots are objectionable in that they expose the surface of the metal sheets below them tothe corrosive action of the elements, which is oftentimes sufficient to ruin an entire sheet of metal. 'Where the lead is not heated beyond its melting point, as under my process, these oxd spots are eliminated, since the lead is not heated to a temperature where it will oxidize.

My improved process further consists in the method 1 employ for cleaning the exit rolls 12-12. As is Well known in the art, spelter will form on these rolls as an amalgamation which must be removed as often, sometimes, as twice a week. 1n order to clean these rolls under present methods, it is necessary to entirely remove them, which is an expensive and laborious process. Now when the rolls are reinserted, they will be only half subn'ierged in the spelter, thereby remaining colder on top than at the bottom, which irregular heating causes them to buckle. Because of their uneven contact with the metal sheets, buckled rolls vvilldis- I tribute an uneven coating of spelter upon them, generally forming a thin coating near the edge of those sheets and' a thicker coatino' on their middle portions.

i y improved process for cleaning these carrying out this part of my process, 1 prefy erably employ the following means:

Referring to the drawings, the numerals 13 13 designate a pair of parallel standards mounted at one side of the galvanizing ma chine in a position' to bring their overhanging ends 1l above the ends of the rolls 12, while similar standards 15 15 are mounted at the other side of the machine to bring ltheir ends 16 above the opposite ends of said rolls. At one end the rolls 12 arepivotally supported by a ll-shaped member 17, while. the opposite ends of said rolls are likewise supported by aV similar Ll shaped member 18. The upperends of the ll-shaped member 17, which are threaded, loosely pass through openings provided in the overhanging ends 16 of the standards, While the upper ends of the U-shaped member 18, which also are threaded, loosely pass through openings provided in the overhanging ends lfl of the standards 13. d lock nut 19 is threaded on each threaded end of the U-shaped members, below its respective overhanging standard end, while a nut 20 to which a handle 21 is secured, is threaded on each threaded end of the U-shaped members aboveits respective overhanging standardend. When the handles 21 .are turned clockwise, they will raise the U-shaped members 17 and 18, and with them the rolls 12; while when said handles and the lock nuts 19 are turned in the opposite direction, they will permit gravity to lower said rolls.

When it is desired to clean said rolls 12,

the handles 21 and lock nuts 19 are-turned a suiiicient distance to permit the rolls to sink in the lead until they are completely submerged in it. The lead, which has previously been heated, or is then heated, beyond its melting point,will thoroughly remove the accumulated scale from the peripheries` of these rolls Wit-hout exposing them to the uneven ten'iperatures that cause them to buckle when they are only half submerged.

While therolls 12 are thus submerged in I the lead, the dross which has formed in the s lter above, may be readily spooned out. llider present methods, the entire guides have to be removed to takeout the large erations in a greater length of time, under my improved process the rolls canbe cleaned and the dross dipped out by one man in approximately one half hour. Having described my invention, I claim:

1. The process of galvamzing metal, which comprises passing it through a preparing agent 'and a galvanizing agent above a part of the surface of the latter and heated by independent means.

2. The process of galvanizing' metal, which comprises, first passing it through a preheating agentand thereafter through a galvamzmg agent resting upon a portionl of the surface of the latter but maintained at its approximate melting point by independent heating means. l

V3. The processl of galvanizing metal, which comprises first passing it through molten lead, and thereafter through spelter resting upon a part of the surface of the latter but maintained at its approximate melting point by independent heating means.

4. The process of producing a coating of desired thickness on metal, which comprises passing the latter through s elter in measured quantity, then through ead, and thereafter through spelter, causing the spelter to occupy but a small portion of the surface of the lead and maintaining said spelter at its approximate melting point by independent heating means.

5. The process of galvanizing metal which ycomprises using lead in conjunction with shelter, and disposing the latter upon only a portion of the surface of the lead, whose temperature is maintained at a point that will not permit it to absorb spelter.

6.A The process of galvanizing metal, which comprises passing it through lead and then between exit rolls immersed in spelter, and maintaining said rolls in a clean state by periodically submerging them in the lead heated to a sufficient temperature to remove the scale from said rolls without exposing them to any uneven temperatures that would cause them to buckle.

In testimony whereof I have hereunto set my hand this 31st day of December, 1918.

ROBERT C. STEFFEN. Witness: HOWARD SMITH. 

